The 1 RB deal, was only going to be for the 20 man league. With only 32 NFL starting running backs, it would be tight trying to get 40 RBs on the rosters. It will be 2 RBs and a flex spot in the 12 man leagues.
I will go ahead and split the two leagues tonight, and if its cool with Ziggy I'll repost the sign up info in the main forum so that the guys that don't check the fantasy forum on the reg will see it too.
Again, look through the league sites and let me know what you think.